using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

using System.Collections.ObjectModel;

​

using System.Text.Json;

using System.Text.Json.Serialization;

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/66495660/net-5-0-signature-change-of-system-text-json-jsonserializer-deserialize

​

#nullable enable

​

    public class MyClass : IJsonOnDeserialized 

    {

        void IJsonOnDeserialized.OnDeserialized() => PostSerialisation();

​

        internal void PostSerialisation()

        {

            //do stuff

            Console.WriteLine("PostSerialisation() called");

            PostSerialisationCalled = true;

        }

        [JsonIgnore]

        public bool PostSerialisationCalled { get; private set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var myClass = JsonSerializer.Deserialize<MyClass>("{}");

            Assert.IsTrue(myClass?.PostSerialisationCalled);

        }   

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}), {2}", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine("System.Text.Json version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​